[X86] Fix typo in comment. NFC

Author: topperc

llvm/lib/Target/X86/X86ISelLowering.cpp

@@ -19584,7 +19584,7 @@ SDValue X86TargetLowering::LowerFP_TO_INT(SDValue Op, SelectionDAG &DAG) const {
     return DAG.getNode(ISD::TRUNCATE, dl, VT, Res);
   }
 
-  // If this is a SINT_TO_FP using SSEReg we're done.
+  // If this is a FP_TO_SINT using SSEReg we're done.
   if (UseSSEReg && IsSigned)
     return Op;